The Richardson-Lucy (RL) deconvolution (RL-deconv) is one of the most widely used techniques for the image deblurring and denoising applications. However, RL-deconv method faces a severe issues for the signal characteristics that follows a non-continuous, exponentially-decaying function. The main reason is due to the inherent ringing errors in the process of Iterative Expectation–Maximization Algorithm.This talk will address this issue including the machanism of the ringing first, then will propose the techniques allowing to alleviate this issue.